The present invention relates generally to a package for solid state electronic flow sensors compatible with liquids or gases.
Typical flow sensors use solid state sensing elements that are not compatible with liquids. Moreover, these devices require complicated packaging schemes to mount the sensing element and to protect that element from the fluid passing through the flow sensor package.
A packaging scheme is known for a pressure gauge such that the pressure gauge can be used to detect the pressure of either a liquid or a gas. The package of this pressure gauge includes a solid state pressure sensing element and elastomeric seals. The pressure gauge detects any change in pressure of a fluid. One of the elastomeric seals is conductive so as to connect signals from the solid state pressure sensing element to electrical leads that exit the housing of the pressure gauge. This type of pressure gauge is shown in U.S. Pat. No. 5,184,107 issued to Dean J. Maurer on Feb. 2, 1993. This pressure gauge, however, is not a flow sensor and, therefore, is not in the fluid channel.
The present invention integrates a pressure sensing element and a restriction into a low-cost, highly-manufacturable flow sensor package. This packaging arrangement exposes the pressure sensing element to the gas or fluid flow but protects the pressure sensing element from the gas or fluid without the need for other protective devices.
The following summary of the invention is provided to facilitate an understanding of some of the innovative features unique to the present invention and is not intended to be a full description. A full appreciation of the various aspects of the invention can be gained by taking the entire specification, claims, drawings, and abstract as a whole.
In accordance with one aspect of the present invention, a flow sensor package comprises a housing, a sensing element, a restriction, and an elastomeric seal. The housing has an inlet port, an outlet port, and first and second channels between the inlet port and the outlet port. The sensing element is in the first channel. The restriction is in the second channel. The elastomeric seal engages the sensing element so as to prevent flow of a gas or fluid through the first channel.
In accordance with another aspect of the present invention, a flow sensor package comprises a housing, a sensing element, a restriction, and an elastomeric seal. The housing has an inlet port, an outlet port, and first and second channels between the inlet port and the outlet port. The sensing element is in the first channel. The restriction is in the second channel, and permits flow of a liquid through the inlet port, the second channel, and the outlet port. The sensing element senses a pressure drop across the restriction. The elastomeric seal engages the sensing element so as to prevent flow of a liquid through the first channel.
In accordance with yet another aspect of the present invention, a method of determining flow rate through a flow conductor comprises the following steps: creating a pressure drop within a housing; sensing the pressure drop, preferably using a sensing element mounted within the housing; sealing the sensing element within the housing using a seal; and communicating a signal from the sensing element through the seal to an exterior of the housing.
The novel features of the present invention will become apparent to those of skill in the art upon examination of the following detailed description of the invention or can be learned by practice of the present invention. It should be understood, however, that the detailed description of the invention and the specific example presented, while indicating certain embodiments of the present invention, are provided for illustration purpose only because various changes and modifications within the scope of the invention will become apparent to those of skill in the art from the detailed description of the invention and claims that follow.